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title: "Connecting to Union"
sidebar:
  order: 0
---

Opening a connection to Union is fully permissionless for any network with a supported light client. For new 
ecosystems, a light client can be deployed permissionlessly soon, until then a governance proposal is necessary.

The process for opening a connection is different depending on the ecosystem that initiates the handshake. 
We provide a few guides for common SDKs, such as Cosmos, Arbitrum, Movementlabs.xyz, and L2s using Ethereum as a settlement layer. 
The documentation for most of these is a work in progress.

For smart contracts and applications deployed on existing ecosystems, it is best to leverage the pre-existing, 
immutable Union Gateway contracts. These allow for general message passing and asset transfers.

Unionlabs offers a curated [GraphQL API](/integrations/api/graphql/) with a live [GraphiQL playground](/reference/graphql)
and a [TypeScript SDK](/integrations/typescript/) to build applications and frontends.
